Mortality of Oryzophagus oryzae (Costa Lima, 1936) (Coleoptera: Curculionidae) and Spodoptera frugiperda (J E Smith, 1797) (Lepidoptera: Noctuidae) Larvae Exposed to Bacillus thuringiensis and Extracts of Melia azedarach

Brazilian Archives of Biology and Technology

Diouneia Lisiane Berlitz²  Aline Oliboni De Azambuja²  Alessandra Sebben²  Jaime Vargas De Oliveira¹  Lidia Mariana Fiuza² 

[1] ,Universidade Vale do Rio dos Sinos Centro de Ciências da Saúde São Leopoldo RS ,Brasil

关键词: Alternative pest control;    entomopathogenic bacteria;    insecticidal activity;    botanical insecticidal;   

DOI  :  10.1590/S1516-89132012000500012

来源: SciELO

【 摘 要 】

Oryzophagus oryzae (Costa Lima 1936) (Coleoptera: Curculionidae) and Spodoptera frugiperda (J E Smith, 1797) (Lepidoptera: Noctuidae) cause important crop losses in southern Brazil. Control is possible by the use of the bacteria Bacillus thuringiensis and extracts of Melia azedarach. This study aimed to evaluate the mortality, in vivo, of O. oryzae and S. frugiperda submitted to two isolates of B. thuringiensis and the aqueous extract of M. azedarach. The LC50 for O. oryzae due to bacteria was 5.40μg/mL (Bt 2014-2) and due to plant extract 0.90μg/mL. For S. frugiperda, the Bt 1958-2 bacterial suspension (1.10(10)UFC/mL) caused a 100% of corrected mortality, showing that the purified Cry proteins caused a CL10 of 268μg/mL five days after the treatments, and M. azedarach toxins caused a CL50 173μg/mL four days after the treatment. Corrected mortality for O. oryzae and S. frugiperda in the interaction between the bacterial and plant toxins were 11 and 6%, respectively. In the PCR analysis of B. thuringiensis isolates, DNA fragments were enlarged and corresponded to the cry1 and cry2 genes for Bt 1958-2. Thus, it could be concluded that the usage of Bt 2014-2 active against O. oryzae larvae; Bt 1958-2 for S. frugiperda and, for both the insect species, M. azedarach aqueous extract could be used.

【 授权许可】

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